Artificial turf yarn

ABSTRACT

An artificial turf comprising a turf yarn prepared from an ethylene-based polymer composition comprising less than or equal to 100 percent by weight of the units derived from ethylene; and less than 30 percent by weight of units derived from one or more α-olefin comonomers; wherein said ethylene-based polymer composition is characterized by having a Comonomer Distribution Constant of equal to or greater than 40, a vinyl unsaturation of less than 100 vinyls per one million carbon atoms present in the backbone of the ethylene-based polymer composition; a zero shear viscosity ratio (ZSVR) equal to or greater than 1.75; a density in the range of 0.915 to 0.930 g/cm 3 , a melt index (1 2 ) in the range of from 0.8 to 5 g/10 minutes, a molecular weight distribution (M w /M n ) in the range of from 2 to 3.6, and a molecular weight distribution (M z /M w ) equal to or less than 3; and wherein the turf yarn exhibits one or more of the following properties (a) shrink of less than 4.8%, and (b) curl of less than 0.5 is provided.

FIELD OF INVENTION

The instant invention relates artificial turf.

BACKGROUND OF THE INVENTION

Artificial turf yarn prepared from polyethylene at densities of about0.900 g/cm³ typically exhibit higher shrink values than those preparedfrom polyethylene having densities of about 0.935g/cm³. Lower densitypolyethylene provides the turf yarn with higher durability, softness,and resiliency. Turf yarns prepared from lower density polyethylene alsoexhibit higher shrink. Turf yarns with high shrink shorten when thetufted carpet is coated with a polyurethane or latex backing, therebyreducing the pile height. In order to compensate for shrink, longeryarns are tufted to account for the length reduction caused by highshrink. Residual shrink in the yarn reflects potential energy andstresses in the material which can be released by heat or time in theinstalled artificial turf, which can cause yarn breaks or curling.

SUMMARY OF THE INVENTION

The instant invention is an artificial turf and method of preparingsame. In one embodiment, the instant invention provides an artificialturf comprising a turf yarn prepared from an ethylene-based polymercomposition comprising: less than or equal to 100 percent by weight ofthe units derived from ethylene; and less than 30 percent by weight ofunits derived from one or more α-olefin comonomers; wherein saidethylene-based polymer composition is characterized by having aComonomer Distribution Constant of equal to or greater than 40, a vinylunsaturation of less than 100 vinyls per one million carbon atomspresent in the backbone of the ethylene-based polymer composition; azero shear viscosity ratio (ZSVR) equal to or greater than 1.75; adensity in the range of 0.915 to 0.930 g/cm³, a melt index (I₂) in therange of from 0.8 to 5 g/10 minutes, a molecular weight distribution(M_(w)/M_(n)) in the range of from 2 to 3.6, and a molecular weightdistribution (M_(z)/M_(w)) equal to or less than 3; and wherein the turfyarn exhibits one or more of the following properties (a) shrink of lessthan 4.8%, and (b) curl of less than 0.5.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form that is exemplary; it being understood, however, thatthis invention is not limited to the precise arrangements andinstrumentalities shown.

FIG. 1 is a schematic illustrating measurements used in calculatingcurl.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention is an artificial turf. The term “artificial turf,”as used herein, is a carpet-like cover having substantially upright, orupright, polymer strands of artificial turf yarn projecting upwardlyfrom a substrate. The term “artificial turf yarn” or “turf yarn” or“yarn” as used herein, includes fibrillated tape yarn, co-extruded tapeyarns, monotape and monofilament yarn. A “fibrillated tape” or“fibrillated tape yarn,” is a cast extruded film cut into tape(typically about 1 cm width), the film stretched and long slits cut(fibrillated) into the tape giving the tape the dimensions of grassblades. A “monofilament yarn” is extruded into individual yarn orstrands with a desired cross-sectional shape and thickness followed byyarn orientation and relaxation in hot ovens. The artificial turf yarnforms the polymer strands for the artificial turf.

The artificial turf comprises a turf yarn prepared from anethylene-based polymer composition comprising: less than or equal to 100percent by weight of the units derived from ethylene; and less than 30percent by weight of units derived from one or more α-olefin comonomers;wherein said ethylene-based polymer composition is characterized byhaving a Comonomer Distribution Constant of equal to or greater than 40,a vinyl unsaturation of less than 100 vinyls per one million carbonatoms present in the backbone of the ethylene-based polymer composition;a zero shear viscosity ratio (ZSVR) equal to or greater than 1.75; adensity in the range of 0.915 to 0.930 g/cm³, a melt index (I₂) in therange of from 0.8 to 5 g/10 minutes, a molecular weight distribution(M_(w)/M_(n)) in the range of from 2 to 3.6, and a molecular weightdistribution (M_(z)/M_(w)) equal to or less than 3; and wherein the turfyarn exhibits one or more of the following properties (a) shrink of lessthan 4.8%, and (b) curl of less than 0.5.

The ethylene-based polymer composition comprises (a) less than or equalto 100 percent, for example, at least 70 percent, or at least 80percent, or at least 90 percent, by weight of the units derived fromethylene; and (b) less than 30 percent, for example, less than 25percent, or less than 20 percent, or less than 10 percent, by weight ofunits derived from one or more α-olefin comonomers. The term“ethylene-based polymer composition” refers to a polymer that containsmore than 50 mole percent polymerized ethylene monomer (based on thetotal amount of polymerizable monomers) and, optionally, may contain atleast one comonomer.

The α-olefin comonomers typically have no more than 20 carbon atoms. Forexample, the α-olefin comonomers may preferably have 3 to 10 carbonatoms, and more preferably 3 to 8 carbon atoms. Exemplary α-olefincomonomers include, but are not limited to, propylene, 1-butene,1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and4-methyl-l-pentene. The one or more α-olefin comonomers may, forexample, be selected from the group consisting of propylene, 1-butene,1-hexene, and 1-octene; or in the alternative, from the group consistingof 1-hexene and 1-octene.

In one embodiment, ethylene-based polymer composition has a comonomerdistribution profile comprising a monomodal distribution or a bimodaldistribution in the temperature range of from 35° C. to 120° C.,excluding purge.

Any conventional ethylene (co)polymerization reaction processes may beemployed to produce the ethylene-based polymer composition. Suchconventional ethylene (co)polymerization reaction processes include, butare not limited to, slurry phase polymerization process, solution phasepolymerization process, and combinations thereof using one or moreconventional reactors, e.g. loop reactors, stirred tank reactors, batchreactors in parallel, series, and/or any combinations thereof.

In one embodiment, the ethylene-based polymer is prepared via a processcomprising the steps of: (a) polymerizing ethylene and optionally one ormore α-olefins in the presence of a first catalyst to form asemi-crystalline ethylene-based polymer in a first reactor or a firstpart of a multi-part reactor; and (b) reacting freshly supplied ethyleneand optionally one or more α-olefins in the presence of a secondcatalyst comprising an organometallic catalyst thereby forming anethylene-based polymer composition in at least one other reactor or alater part of a multi-part reactor, wherein at least one of the catalystsystems in step (a) or (b) comprises a metal complex of a polyvalentaryloxyether corresponding to the formula:

wherein M³ is Ti, Hf or Zr, preferably Zr;

Ar⁴ is independently in each occurrence a substituted C₉₋₂₀ aryl group,wherein the substituents, independently in each occurrence, are selectedfrom the group consisting of alkyl; cycloalkyl; and aryl groups; andhalo-, trihydrocarbylsilyl- and halohydrocarbyl-substituted derivativesthereof, with the proviso that at least one substituent lacksco-planarity with the aryl group to which it is attached;

T⁴ is independently in each occurrence a C₂₋₂₀ alkylene, cycloalkyleneor cycloalkenylene group, or an inertly substituted derivative thereof;

R²¹ is independently in each occurrence hydrogen, halo, hydrocarbyl,trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl, alkoxy ordi(hydrocarbyl)amino group of up to 50 atoms not counting hydrogen;

R³ is independently in each occurrence hydrogen, halo, hydrocarbyl,trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl, alkoxy or amino ofup to 50 atoms not counting hydrogen, or two R³ groups on the samearylene ring together or an R³ and an R²¹ group on the same or differentarylene ring together form a divalent ligand group attached to thearylene group in two positions or join two different arylene ringstogether; and

R^(D) is independently in each occurrence halo or a hydrocarbyl ortrihydrocarbylsilyl group of up to 20 atoms not counting hydrogen, or 2R^(D) groups together are a hydrocarbylene, hydrocarbadiyl, diene, orpoly(hydrocarbyl)silylene group.

In general, the ethylene-based polymer composition may be produced via asolution polymerization according to the following exemplary process.All raw materials (ethylene, 1-octene) and the process solvent (a narrowboiling range high-purity isoparaffinic solvent commercially availableunder the tradename Isopar E from ExxonMobil Corporation) are purifiedwith molecular sieves before introduction into the reaction environment.Hydrogen is supplied in pressurized cylinders as a high purity grade andis not further purified. The reactor monomer feed (ethylene) stream ispressurized via mechanical compressor to a pressure that is above thereaction pressure, approximate to 750 psig. The solvent and comonomer(1-octene) feed is pressurized via mechanical positive displacement pumpto a pressure that is above the reaction pressure, approximately 750psig. The individual catalyst components are manually batch diluted tospecified component concentrations with purified solvent (Isopar E) andpressurized to a pressure that is above the reaction pressure,approximately 750 psig. All reaction feed flows are measured with massflow meters, independently controlled with computer automated valvecontrol systems.

The continuous solution polymerization reactor system according to thepresent invention consist of two liquid full, non-adiabatic, isothermal,circulating, and independently controlled loops operating in a seriesconfiguration. Each reactor has independent control of all freshsolvent, monomer, comonomer, hydrogen, and catalyst component feeds. Thecombined solvent, monomer, comonomer and hydrogen feed to each reactoris independently temperature controlled to anywhere between 5° C. to 50°C. and typically 40° C. by passing the feed stream through a heatexchanger. The fresh comonomer feed to the polymerization reactors canbe manually aligned to add comonomer to one of three choices: the firstreactor, the second reactor, or the common solvent and then splitbetween both reactors proportionate to the solvent feed split. The totalfresh feed to each polymerization reactor is injected into the reactorat two locations per reactor roughly with equal reactor volumes betweeneach injection location. The fresh feed is controlled typically witheach injector receiving half of the total fresh feed mass flow. Thecatalyst components are injected into the polymerization reactor throughspecially designed injection stingers and are each separately injectedinto the same relative location in the reactor with no contact timeprior to the reactor. The primary catalyst component feed is computercontrolled to maintain the reactor monomer concentration at a specifiedtarget. The two cocatalyst components are fed based on calculatedspecified molar ratios to the primary catalyst component. Immediatelyfollowing each fresh injection location (either feed or catalyst), thefeed streams are mixed with the circulating polymerization reactorcontents with static mixing elements. The contents of each reactor arecontinuously circulated through heat exchangers responsible for removingmuch of the heat of reaction and with the temperature of the coolantside responsible for maintaining isothermal reaction environment at thespecified temperature. Circulation around each reactor loop is providedby a screw pump. The effluent from the first polymerization reactor(containing solvent, monomer, comonomer, hydrogen, catalyst components,and molten polymer) exits the first reactor loop and passes through acontrol valve (responsible for maintaining the pressure of the firstreactor at a specified target) and is injected into the secondpolymerization reactor of similar design. As the stream exits thereactor, it is contacted with a deactivating agent, e.g. water, to stopthe reaction. In addition, various additives such as anti-oxidants, canbe added at this point. The stream then goes through another set ofstatic mixing elements to evenly disperse the catalyst deactivatingagent and additives. Following additive addition, the effluent(containing solvent, monomer, comonomer, hydrogen, catalyst components,and molten polymer) passes through a heat exchanger to raise the streamtemperature in preparation for separation of the polymer from the otherlower boiling reaction components. The stream then enters a two stageseparation and devolatilization system where the polymer is removed fromthe solvent, hydrogen, and unreacted monomer and comonomer. The recycledstream is purified before entering the reactor again. The separated anddevolatized polymer melt is pumped through a die specially designed forunderwater pelletization, cut into uniform solid pellets, dried, andtransferred into a hopper.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is characterized by having a ComonomerDistribution Constant (CDC) of equal to or greater than 40. Allindividual values and subranges of equal to or greater than 40 areincluded herein and disclosed herein; for example, the CDC can be from alower limit of 40, 80, 100, 150, 200, 250, 300, or 350. For example, theCDC of the ethylene-based polymer composition may be from 40 to 400, orfrom 100 to 300, or from 100 to 200, or from 40 to 80, or from 80 to 200or from 80 to 400.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is characterized by having a vinylunsaturation of less than 100 vinyls per one million carbon atomspresent in the backbone of the ethylene-based polymer composition(vinyls/1,000,000 C). All individual values and subranges from less than100 vinyls/1,000,000 C are included herein and disclosed herein; forexample, the amount of vinyl unsaturation can be from a upper limit of50, 60, 70, 80, 90 or 100 vinyls/1,000,000 C.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is characterized by having a totalunsaturation of less than or equal to 150 total unsaturations per onemillion carbon atoms present in the backbone of the ethylene-basedpolymer composition (total unsaturations/1,000,000 C). All individualvalues and subranges from less than or equal to 150 totalunsaturations/1,000,000 C are included herein and disclosed herein. Forexample, the amount of total unsaturation can be less than or equal to150, or less than or equal to 125, or less than or equal to 100, or lessthan or equal to 70, or less than or equal to 50/1,000,000 C.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is characterized by having a zero shearviscosity ratio (ZSVR) equal to or greater than 1.75. All individualvalues and subranges of equal to or greater than 1.75 are includedherein and disclosed herein; for example, the ZSVR of the ethylene-basedpolymer can be from a lower limit of 1.75, 2, 2.2, 2.4, 2.6, 2.8 or 2.9.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is further characterized by having a densityin the range of 0.915 to 0.930 g/cm³. All individual values andsubranges from 0.915 to 0.930 g/cm³ are included herein and disclosedherein; for example, the density can be from a lower limit of 0.915,0.918, 0.920, 0.925, or 0.928 g/cm³ to an upper limit of 0.918, 0.920,0.925, 0.928, or 0.930 g/cm³. For example, the density may be in therange of from 0.915 to 0.930 g/cm³, or from 0.902 to 0.928 g/cm³, orfrom 0.918 to 0.930 g/cm³.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is further characterized by having a meltindex (I₂) in the range of from 0.8 to 5 g/10 minutes. All individualvalues and subranges from 0.8 to 5 g/10 minutes are included herein anddisclosed herein; for example, the I₂ can be from a lower limit of 0.8,1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 g/10 minutes to an upper limit of 1.5,2, 2.5, 3, 3.5, 4, 4.5 or 5 g/10 minutes. For example, the I₂ may be inthe range of from 0.8 to 5, or from 1.5 to 5, or from 1 to 3.5, or from2 to 4 g/10 minutes, or from 3 to 4 g/10 minutes.

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is further characterized by having a molecularweight distribution (M_(w)/M_(n)) in the range of from 2 to 3.6. Allindividual values and subranges from 2 to 3.6 are included herein anddisclosed herein; for example, the M_(w)/M_(n) can be from a lower limitof 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4 or 3.5 to an upper limit of 2.1,2.3, 2.5, 2.7, 2.9, 3.1, 3.3, 3.5, or 3.6. For example, the M_(w)/M_(n)may be in the range of from 2 to 3.6, or in the alternative, theM_(w)/M_(n) may be in the range of from 2 to 3, or in the alternative,the M_(w)/M_(n) may be in the range of from 2.4 to 3.6, or in thealternative, the M_(w)/M_(n) may be in the range of from 2.4 to 3.4,

The ethylene-based polymer composition useful in embodiments of theinventive artificial turf is further characterized by having a molecularweight distribution (M_(z)/M_(w)) in the range of from less than 3. Allindividual values and subranges from less than 3 are included herein anddisclosed herein; for example, the M_(z)/M_(w) can be from an upperlimit of 2.4, 2.6, 2.8 or 3.

A turf yarn prepared from the ethylene-based polymer exhibits one ormore of the following properties: (a) shrink of less than 4.8%, and (b)curl of less than 0.5.

In one embodiment, the ethylene-based polymer composition comprises lessthan or equal to 100 parts, for example, less than 10 parts, less than 8parts, less than 5 parts, less than 4 parts, less than 1 parts, lessthan 0.5 parts, or less than 0.1 parts, by weight of metal complexresidues remaining from a catalyst system comprising a metal complex ofa polyvalent aryloxyether, as described hereinabove, per one millionparts of the ethylene-based polymer composition. The metal complexresidues remaining from the catalyst system comprising a metal complexof a polyvalent aryloxyether in the ethylene-based polymer compositionmay be measured by x-ray fluorescence (XRF), which is calibrated toreference standards. The polymer resin granules can be compressionmolded at elevated temperature into plaques having a thickness of about⅜ of an inch for the x-ray measurement in a preferred method. At verylow concentrations of metal complex, such as below 0.1 ppm, ICP-AES(inductively coupled plasma-atomic emission spectroscopy) would be asuitable method to determine metal complex residues present in theethylene-based polymer composition.

Any of the foregoing artificial turf yarns may include one or moreadditives. Nonlimiting examples of suitable additives includeantioxidants, pigments, colorants, UV stabilizers, UV absorbers, curingagents, cross linking co-agents, boosters and retardants, processingaids, fillers, coupling agents, ultraviolet absorbers or stabilizers,antistatic agents, nucleating agents, slip agents, plasticizers,lubricants, viscosity control agents, tackifiers, anti-blocking agents,surfactants, extender oils, acid scavengers, and metal deactivators.Additives can be used in amounts ranging from less than about 0.01 wt %to 10 wt % based on the weight of the composition.

Nonlimiting examples of pigments include inorganic pigments that aresuitably colored to provide an aesthetic appeal including various shadesof green, white (TiO₂, rutile), iron oxide pigments, and any othercolor.

Examples of antioxidants are as follows, but are not limited to:hindered phenols such astetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydro-cinnamate)] methane;bis[(beta-(3,5-ditert-butyl-4-hydroxybenzyl)-methylcarboxyethyl)]sulphide,4,4′-thiobis(2-methyl-6-tert-butylphenol),4,4′-thiobis(2-tert-butyl-5-methylphenol),2,2′-thiobis(4-methyl-6-tert-butylphenol), and thiodiethylenebis(3,5-di-tert-butyl-4-hydroxy)hydrocinnamate; phosphites andphosphonites such as tris(2,4-di-tert-butylphenyl)phosphite anddi-tert-butylphenyl-phosphonite; thio compounds such asdilaurylthiodipropionate, dimyristylthiodipropionate, anddistearylthiodipropionate; various siloxanes; polymerized2,2,4-trimethyl-1,2-dihydroquinoline,n,n′-bis(1,4-dimethylpentyl-p-phenylenediamine), alkylateddiphenylamines, 4,4′-bis(alpha, alpha-demthylbenzyl)diphenylamine,diphenyl-p-phenylenediamine, mixed di-aryl-p-phenylenediamines, andother hindered amine antidegradants or stabilizers. Antioxidants can beused in amounts of about 0.1 to about 5 wt % based on the weight of thecomposition

Examples of processing aids include but are not limited to metal saltsof carboxylic acids such as zinc stearate or calcium stearate; fattyacids such as stearic acid, oleic acid, or erucic acid; fatty amidessuch as stearamide, oleamide, erucamide, or n,n′-ethylenebisstearamide;polyethylene wax; oxidized polyethylene wax; polymers of ethylene oxide;copolymers of ethylene oxide and propylene oxide; vegetable waxes;petroleum waxes; non ionic surfactants; and polysiloxanes. Processingaids can be used in amounts of about 0.05 to about 5 wt % based on theweight of the composition.

Examples of UV stabilizers and UV absorbers include but are not limitedto hindered amine light stabilizers, benzophenone, benzotriazole,hydroxyphenyl triazine, 2-(2′-hydroxyphenyl)benzotriazoles, UVINOL 3000,TINUVIN P, IRGANOX 1098, UVINOL 3008, LAVINIX BHT, TINUVIN 320, IRGANOX1010, IRGANOX 1076, and IRGAFOS 168. UVINOL, TINUVIN, IRGANOX ANDIRGAFOS products are available from BASF.

A turf yarn prepared from the ethylene-based polymer may exhibit eitheror both of the defined shrink and curl characteristics. For thoseembodiments in which the turf yarn exhibits the specified shrinkcharacteristic, all individual values and subranges of less than 4.8%are included herein and disclosed herein; for example, the shrink can befrom an upper limit of 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6% or 4.8%. Forthose embodiments in which the turf yarn exhibits the specified curlcharacteristic, all individual values and subranges of less than 0.5 areincluded herein and disclosed herein; for example, the shrink can befrom an upper limit of 0.3, 0.34, 0.38, 0.4, 0.44, 0.48 or 0.5.

A turf yarn made from the ethylene-based polymer may optionally exhibitseveral other characteristics. In some embodiments, a turf yarn madefrom the ethylene-based polymer may exhibit one or both of the followingproperties: (a) elongation at break of at least 70%; and (b) stabilityof at least 0.9 cN/dtex. All individual values and subranges from atleast 70% are included herein and disclosed herein; for example, theelongation at break can be from a lower limit of 70%, 74, 78, 81, or83%. Likewise, all individual values and subranges from at least 0.9cN/dtex are included herein and disclosed herein; for example, thestability can be from a lower limit of 0.9, 1.0, 1.02, 1.05, 1.08, 1.1,1.12, 1.14, or 1.16.

In an alternative embodiment, the instant invention further provides amethod of preparing an artificial turf comprising selecting anethylene-based polymer composition comprising less than or equal to 100percent by weight of the units derived from ethylene; and less than 30percent by weight of units derived from one or more α-olefin comonomers;wherein said ethylene-based polymer composition is characterized byhaving a Comonomer Distribution Constant of equal to or greater than 40,a vinyl unsaturation of less than 100 vinyls per one million carbonatoms present in the backbone of the ethylene-based polymer composition;a zero shear viscosity ratio (ZSVR) equal to or greater than 1.75; adensity in the range of 0.915 to 0.930 g/cm³, a melt index (1₂) in therange of from 0.8 to 5 g/10 minutes, a molecular weight distribution(M_(w)/M_(n)) in the range of from 2 to 3.6, and a molecular weightdistribution (M_(z)/M_(w)) equal to or less than 3; and preparing a turfyarn from the ethylene-based polymer composition.

In an alternative embodiment, the instant invention provides anartificial turf, and method of producing the same, in accordance withany of the preceding embodiments, except that the turf yarn exhibits oneor more of the following properties (a) shrink of less than 4.8%, and(b) curl of less than 0.5.

In an alternative embodiment, the instant invention provides anartificial turf, and method of producing the same, in accordance withany of the preceding embodiments, except that the turf yarn exhibits ashrink of less than 4.5% (e.g., from 3.5% to 4.5%)

In an alternative embodiment, the instant invention provides anartificial turf, and method of producing the same, in accordance withany of the preceding embodiments, except that the turf yarn exhibits acurl of less than 0.4 (e.g., from 0.25 to 0.4).

In an alternative embodiment, the instant invention provides anartificial turf, and method of producing the same, in accordance withany of the preceding embodiments, except that the ethylene-based polymercomposition has an I₂ from 3 to 4.

In an alternative embodiment, the instant invention provides anartificial turf, and method of producing the same, in accordance withany of the preceding embodiments, except that the turf yarn exhibits anelongation at break of at least 65%.

In an alternative embodiment, the instant invention provides anartificial turf, and method of producing the same, in accordance withany of the preceding embodiments, except that the turf yarn exhibits astability of 0.9 cN/dtex.

Artificial Turf Yarn Production

The turf yarn may be made using any appropriate process for theproduction of artificial turf yarn from polymer compositions. Thefollowing describes one such process.

Turf yarns may be made by extrusion. Typical turf yarn extruders areequipped with a single PE/PP general purpose screw and a melt pump(“gear pump” or “melt pump”) to precisely control the consistency ofpolymer volume flow into the die. Turf yarn dies have multiple singleholes for the individual filaments distributed over a circular orrectangular spinplate. The shape of the holes corresponds to the desiredyarn crossection profile, including for example, rectangular, dog-bone,and v-shaped. A standard spinplate has 50 to 160 die holes of specificdimensions. Lines typically have output rates from 150 kg/h to 350 kg/h.

The turf yarns are typically extruded into a water-bath with typicaldie-water-bath distance of from 16 to 40 mm. Coated guiding bars in thewater redirect the yarn filaments towards the first take off set ofrollers. The linear speed of this set of rollers typically vary from 15to 70 m/min. The takeoff set of rollers can be heated and used topreheat the yarn after the waterbath before entering the oven.

A yarn is passed over this first set of rollers, and then drawn througha heated air or water bath oven. The first oven is either a hot air ovenwith co- or countercurrent hot air flow which can be operated from 50 to150° C. or a hot water-oven wherein the yarn is oriented at temperaturesfrom 50 to 98° C. At the exit of the oven, the yarn is passed onto asecond set of rollers that are run at a different (higher or lower)speed than the first set of rollers. The linear velocity ratio of therollers after the oven to the rollers in front of the oven is referredto as either a stretching or relaxation ratio. In a three oven process,there are a total of four sets of rollers; a first set of rollers beforethe first oven, a second set of rollers between the first and secondoven, a third set of roller between the second and third ovens, and afourth set of rollers following the third oven.

EXAMPLES

The following examples illustrate the present invention but are notintended to limit the scope of the invention.

Each of Inventive Composition Examples (Inv. Comp. Ex.) 1-3 contained100 wt % of an ethylene-based polymer composition. ComparativeComposition Example (Comp. Composition Ex.) 1 contained 100% ELITE 5230G(a polyethylene commercially available from The Dow Chemical Company).Comparative Composition Example 2 contained 100% DOWLEX 2108G (a LinearLow Density Polyethylene commercially available from The Dow ChemicalCompany). Comparative Composition Example 3 contained 90 wt % ELITE5230G and 10 wt % DOWLEX 2108G. Tables 1-5 provide various propertiesfor Inventive Composition Examples 1-3 and Comparative CompositionExamples 1-3.

TABLE 1 Mn Mp Mw Mz (g/mol) (g/mol) (g/mol) (g/mol) Mw/Mn Mz/Mw Inv.Comp. 31799 56763 70176 129086 2.21 1.84 Ex. 1 Inv. Comp. 20900 3477871948 167252 3.44 2.32 Ex. 2 Inv. Comp. 30203 54350 73442 144152 2.431.96 Ex. 3 Comp. 25592 62374 75116 152617 2.94 2.03 Composition Ex. 1Comp. 27562 57635 88966 232743 3.23 2.62 Composition Ex. 2

TABLE 2 Density, g/cm³ I₂ (g/10 min) I₁₀/I₂ Inv. Comp. Ex. 1 0.920 4.07.2 Inv. Comp. Ex. 2 0.919 3.4 8.5 Inv. Comp. Ex. 3 0.918 3.4 7.0 Comp.Composition Ex. 1 0.916 4.0 6.9 Comp. Composition Ex. 2 0.935 2.6 7.2Comp. Composition Ex. 3* 0.918 3.7 Not available *Values for Comp.Composition Ex. 3 were calculated based upon component polymer values.

TABLE 3 Unsaturation unit/1,000,000 carbon Vinylene Trisubstituted VinylVinylidene Total Inv. Comp. 3 None 18 3 25 Ex. 1 detected (ND) Inv.Comp. 6 ND 39 3 49 Ex. 2 Inv. Comp. 4 ND 41 4 49 Ex. 3 Comp. 56 23 16239 280 Composition Ex. 1 Comp. 24  7 286 24 342 Composition Ex. 2

TABLE 4 Half Half CDI Stdev (° C.) Width (° C.) Width/Stdev CDC Inv.Comp. 0.766 11.518 5.553 0.482 158.9 Ex. 1 Inv. Comp. 0.830 8.846 15.9361.801 46.0 Ex. 2 Inv. Comp. 0.790 9.594 4.742 0.494 159.7 Ex. 3 Comp.0.704 12.441 6.550 0.526 133.7 Composition Ex. 1 Comp. 0.950 9.655 5.0180.520 182.8 Composition Ex. 2 Comp. 0.653 13.085 6.186 0.473 138.2Composition Ex. 3

TABLE 5 Mw(g/mol) ZSV (Pas) ZSVR Inv. Comp. Ex. 1 70176 2420 2.16 Inv.Comp. Ex. 2 71948 3485 2.85 Inv. Comp. Ex. 3 73442 2737 2.07 Comp.Composition Ex. 1 75116 2241 1.56 Comp. Composition Ex. 2 88966 33741.27

Turf Yarn Production

Inventive Turf Yarn Examples (Inv. TY Ex.) 1-3 were prepared fromInventive Composition Examples 1-3, respectively. Each of the InventiveTurf Yarn Examples contained 93.5 percent by weight of the InventiveComposition Example, 6 percent by weight of ARGUS GREEN G16-130UV and0.5 percent by weight of ARGUS ARX/41 PA01 LD process aid (each of whichare commercially available from Argus Additive Plastics GbmH, Buren,Germany). The conditions of monofilament formation and resultingmonofilament properties are shown in Table 6 below. Comparative TurfYarn Example (Comp. TY Ex.) 1 was prepared from 93.5 weight percentComp. Composition Ex. 3, 6 weight percent ARGUS GREEN G16-130UV and 0.5percent by weight of ARGUS ARX/41 PA01 LD process aid. The additiveswere blended with the polymer compositions prior to extrusion. Each ofthe Turf Yarn Examples was prepared on a compact three oven extrusionline from Oerlikon Barmag (Remscheid, Germany) as described hereinabove.The specific conditions of the equipment used in preparing the Turf YarnExamples is provided in Table 6 below. Table 6 further provides physicalproperties for each of the Turf Yarn Examples.

TABLE 6 Comp. TY Inv. TY Inv. TY Inv. TY Ex. 1 Ex. 1 Ex. 2 Ex 3 Die -water mm 45 45 45 45 Temp. rollers 80 80 80 80 before oven #1, ° C.Stretching ratio 5.42 5.00 5.00 5.00 Temp oven 1, ° C. 95 95 95 95 Temp.rollers 110 110 110 110 before oven #2, ° C. Relaxation ratio 0.74 0.790.78 0.80 Temp. oven 2, ° C. 118 118 118 118 Temp rollers 100 100 100100 before oven #3, ° C. Relaxation ratio 1.02 1.03 1.03 1.01 Temp. oven#3, ° C. 115 115 115 115 Temp rollers after 30 30 30 30 oven #3, ° C.Final speed m/min 130 130 130.5 130 Melt pump rpm 36.2 36.2 35 36.2 Toolpressure, bar 100.0 94.7 99.2 91.5 Melt Temperature 234.6 233.7 234.2230.5 ° C. Linear weight 1990 1992 2022 2002 (Titer)/dtex Stability,cN/dtex 1.06 1.15 1.13 1.02 Residual 79.2 86.7 82.1 70.6 Elongation, %Shrink, % 4.9 3.6 3.8 4.2 Curl ratio 0.56 0.39 0.32 0.27

Each of the Inventive and Comparative Turf Yarn Examples. Methods offorming artificial turf are known and disclosed, for example, in PCTPublication 20110330, the disclosure of which is incorporated herein byreference. The Turf Yarn Examples were tested using the curl method fortwist and curl. Inventive Turf Yarn Example 3 showed the lowest twistand curl, corresponding to the lowest residual stress in the yarn.Inventive Turf Yarn Examples 1 and 2 also showed very low twist and curlin comparison to Comparative Turf Yarn Example 1.

Composition Test Methods

Polymer composition test methods include the following:

Density

Samples for density measurement are prepared according to ASTM D 1928.Measurements are made within one hour of sample pressing using ASTMD792, Method B.

Melt Index

Melt index, or I₂, is measured in accordance with ASTM D 1238, Condition190° C./2.16 kg. I₁₀ is measured in accordance with ASTM D 1238,Condition 190° C./10 kg.

Gel Permeation Chromatography (GPC)

The GPC system consists of a Waters (Milford, Mass.) 150° C. hightemperature chromatograph (other suitable high temperatures GPCinstruments include Polymer Laboratories (Shropshire, UK) Model 210 andModel 220) equipped with an on-board differential refractometer (RI).Additional detectors can include an IR4 infra-red detector from PolymerChAR (Valencia, Spain), Precision Detectors (Amherst, Mass.) 2-anglelaser light scattering detector Model 2040, and a Viscotek (Houston,Tex.) 150R 4-capillary solution viscometer. A GPC with the last twoindependent detectors and at least one of the first detectors issometimes referred to as “3D-GPC”, while the term “GPC” alone generallyrefers to conventional GPC. Depending on the sample, either the15-degree angle or the 90-degree angle of the light scattering detectoris used for calculation purposes. Data collection is performed usingViscotek TriSEC software, Version 3, and a 4-channel Viscotek DataManager DM400. The system is also equipped with an on-line solventdegassing device from Polymer Laboratories (Shropshire, UK). Suitablehigh temperature GPC columns can be used such as four 30 cm long ShodexHT803 13 micron columns or four 30 cm Polymer Labs columns of 20-micronmixed-pore-size packing (MixA LS, Polymer Labs). The sample carouselcompartment is operated at 140 ° C. and the column compartment isoperated at 150 ° C. The samples are prepared at a concentration of 0.1grams of polymer in 50 milliliters of solvent. The chromatographicsolvent and the sample preparation solvent contain 200 ppm of butylatedhydroxytoluene (BHT). Both solvents are sparged with nitrogen. Thepolyethylene samples are gently stirred at 160 ° C. for four hours. Theinjection volume is 200 microliters. The flow rate through the GPC isset at 1 ml/minute.

The GPC column set is calibrated before running the Examples by runningtwenty-one narrow molecular weight distribution polystyrene standards.The molecular weight (MW) of the standards ranges from 580 to 8,400,000grams per mole, and the standards are contained in 6 “cocktail”mixtures. Each standard mixture has at least a decade of separationbetween individual molecular weights. The standard mixtures arepurchased from Polymer Laboratories (Shropshire, UK). The polystyrenestandards are prepared at 0.025 g in 50 mL of solvent for molecularweights equal to or greater than 1,000,000 grams per mole and 0.05 g in50 ml of solvent for molecular weights less than 1,000,000 grams permole. The polystyrene standards were dissolved at 80 ° C. with gentleagitation for 30 minutes. The narrow standards mixtures are run firstand in order of decreasing highest molecular weight component tominimize degradation. The polystyrene standard peak molecular weightsare converted to polyethylene M_(w) using the Mark-Houwink K and a(sometimes referred to as α) values mentioned later for polystyrene andpolyethylene. See the Examples section for a demonstration of thisprocedure.

With 3D-GPC, absolute weight average molecular weight (“M_(w,Abs)”) andintrinsic viscosity are also obtained independently from suitable narrowpolyethylene standards using the same conditions mentioned previously.These narrow linear polyethylene standards may be obtained from PolymerLaboratories (Shropshire, UK; Part No.'s PL2650-0101 and PL2650-0102).The systematic approach for the determination of multi-detector offsetsis performed in a manner consistent with that published by Balke,Mourey, et al. (Mourey and Balke, Chromatography Polym., Chapter 12,(1992)) (Balke, Thitiratsakul, Lew, Cheung, Mourey, ChromatographyPolym., Chapter 13, (1992)), optimizing triple detector log (M_(w) andintrinsic viscosity) results from Dow 1683 broad polystyrene (AmericanPolymer Standards Corp.; Mentor, Ohio) or its equivalent to the narrowstandard column calibration results from the narrow polystyrenestandards calibration curve. The molecular weight data, accounting fordetector volume off-set determination, are obtained in a mannerconsistent with that published by Zimm (Zimm, B. H., J. Chem. Phys., 16,1099 (1948)) and Kratochvil (Kratochvil, P., Classical Light Scatteringfrom Polymer Solutions, Elsevier, Oxford, N.Y. (1987)). The overallinjected concentration used in the determination of the molecular weightis obtained from the mass detector area and the mass detector constantderived from a suitable linear polyethylene homopolymer, or one of thepolyethylene standards. The calculated molecular weights are obtainedusing a light scattering constant derived from one or more of thepolyethylene standards mentioned and a refractive index concentrationcoefficient, dn/dc, of 0.104. Generally, the mass detector response andthe light scattering constant should be determined from a linearstandard with a molecular weight in excess of about 50,000 daltons. Theviscometer calibration can be accomplished using the methods describedby the manufacturer or alternatively by using the published values ofsuitable linear standards such as Standard Reference Materials (SRM)1475a, 1482a, 1483, or 1484a. The chromatographic concentrations areassumed low enough to eliminate addressing 2^(nd) viral coefficienteffects (concentration effects on molecular weight).

Crystallization Elution Fractionation (CEF) Method

Comonomer distribution analysis is performed with CrystallizationElution Fractionation (CEF) (PolymerChar in Spain) (B Monrabal et al,Macromol. Symp. 257, 71-79 (2007)). Ortho-dichlorobenzene (ODCB) with600 ppm antioxidant butylated hydroxytoluene (BHT) is used as solvent.Sample preparation is done with autosampler at 160° C. for 2 hours undershaking at 4 mg/ml (unless otherwise specified). The injection volume is300 μl. The temperature profile of CEF is: crystallization at 3° C./minfrom 110° C. to 30° C., the thermal equilibrium at 30° C. for 5 minutes,elution at 3° C./min from 30° C. to 140° C. The flow rate duringcrystallization is at 0.052 ml/min. The flow rate during elution is at0.50 ml/min. The data is collected at one data point/second. CEF columnis packed by The Dow Chemical Company with glass beads at 125 μm±6%(MO-SCI Specialty Products) with ⅛ inch stainless tubing. Glass beadsare acid washed by MO-SCI Specialty with the request from The DowChemical Company. Column volume is 2.06 ml. Column temperaturecalibration is performed by using a mixture of NIST Standard ReferenceMaterial Linear polyethylene 1475a (1.0 mg/ml) and Eicosane (2 mg/ml) inODCB. Temperature is calibrated by adjusting elution heating rate sothat NIST linear polyethylene 1475a has a peak temperature at 101.0° C.,and Eicosane has a peak temperature of 30.0° C. The CEF columnresolution is calculated with a mixture of NIST linear polyethylene1475a (1.0 mg/ml) and hexacontane (Fluka, purum, ≧97.0%, 1 mg/ml). Abaseline separation of hexacontane and NIST polyethylene 1475a isachieved. The area of hexacontane (from 35.0 to 67.0° C.) to the area ofNIST 1475a from 67.0 to 110.0° C. is 50 to 50, the amount of solublefraction below 35.0° C. is <1.8 wt %. The CEF column resolution isdefined in the following equation:

${Resolution} = \frac{\begin{matrix}{{{Peak}\mspace{14mu} {temperature}\mspace{14mu} {of}\mspace{14mu} {NIST}\mspace{14mu} 1475a} -} \\{{Peak}\mspace{14mu} {Temperature}\mspace{14mu} {of}\mspace{14mu} {Hexacontane}}\end{matrix}}{\begin{matrix}{{{Half}\text{-}{height}\mspace{14mu} {Width}\mspace{14mu} {of}\mspace{14mu} {NIST}\mspace{14mu} 1475a} +} \\{{Half}\text{-}{height}\mspace{14mu} {Width}\mspace{14mu} {of}\mspace{14mu} {Hexacontane}}\end{matrix}}$

where the column resolution is 6.0.

Comonomer Distribution Constant (CDC) Method

Comonomer distribution constant (CDC) is calculated from comonomerdistribution profile by CEF. CDC is defined as Comonomer DistributionIndex divided by Comonomer Distribution Shape Factor multiplying by 100as shown in the following equation:

${CDC} = {\frac{{Comonomer}\mspace{14mu} {Distribution}\mspace{14mu} {Index}}{{Comonomer}\mspace{14mu} {Distribution}\mspace{14mu} {Shape}\mspace{14mu} {Factor}} = {\frac{{Comonmer}\mspace{14mu} {Distribution}\mspace{14mu} {Index}}{{Half}\mspace{14mu} {{Width}/{Stdev}}}*100}}$

Comonomer distribution index stands for the total weight fraction ofpolymer chains with the comonomer content ranging from 0.5 of mediancomonomer content (C_(median)) and 1.5 of C_(median) from 35.0 to 119.0°C. Comonomer Distribution Shape Factor is defined as a ratio of the halfwidth of comonomer distribution profile divided by the standarddeviation of comonomer distribution profile from the peak temperature(T_(p)).

CDC is calculated from comonomer distribution profile by CEF, and CDC isdefined as Comonomer Distribution Index divided by ComonomerDistribution Shape Factor multiplying by 100 as shown in the followingEquation:

${CDC} = {\frac{{Comonomer}\mspace{14mu} {Distrubution}\mspace{14mu} {Index}}{{Comonomer}\mspace{14mu} {Distribution}\mspace{14mu} {Shape}\mspace{14mu} {Factor}} = {\frac{{Comonomer}\mspace{14mu} {Distribution}\mspace{14mu} {Index}}{{Half}\mspace{14mu} {{Width}/{Stdev}}}*100}}$

wherein Comonomer distribution index stands for the total weightfraction of polymer chains with the comonomer content ranging from 0.5of median comonomer content (C_(median)) and 1.5 of C_(median) from 35.0to 119.0° C., and wherein Comonomer Distribution Shape Factor is definedas a ratio of the half width of comonomer distribution profile dividedby the standard deviation of comonomer distribution profile from thepeak temperature (Tp).

CDC is calculated according to the following steps:

(A) Obtain a weight fraction at each temperature (7) (w_(T)(T)) from35.0° C. to 119.0° C. with a temperature step increase of 0.200° C. fromCEF according to the following Equation:

∫₃₅^(119.0)w_(T)(T) T = 1

(B) Calculate the median temperature (T_(median)) at cumulative weightfraction of 0.500, according to the following Equation:

∫₃₅^(T_(median))w_(T)(T) T = 0.5

(C) Calculate the corresponding median comonomer content in mole %(C_(median)) at the median temperature (T_(median)) by using comonomercontent calibration curve according to the following Equation:

${\ln \left( {1 - {{comonomerc}\mspace{14mu} {ontent}}} \right)} = {{- \frac{207.26}{273.12 + T}} + 0.5533}$R² = 0.997

(D) Construct a comonomer content calibration curve by using a series ofreference materials with known amount of comonomer content, i.e., elevenreference materials with narrow comonomer distribution (mono-modalcomonomer distribution in CEF from 35.0 to 119.0° C.) with weightaverage M_(w) of 35,000 to 115,000 (measured via conventional GPC) at acomonomer content ranging from 0.0 mole % to 7.0 mole % are analyzedwith CEF at the same experimental conditions specified in CEFexperimental sections;

(E) Calculate comonomer content calibration by using the peaktemperature (T_(p)) of each reference material and its comonomercontent; The calibration is calculated from each reference materialaccording to the following Equation:

${\ln \left( {1 - {{comonomerc}\mspace{14mu} {ontent}}} \right)} = {{- \frac{207.26}{273.12 + T}} + 0.5533}$R² = 0.997

wherein: R² is the correlation constant;

(F) Calculate Comonomer Distribution Index from the total weightfraction with a comonomer content ranging from 0.5*C_(median) to1.5*C_(median), and if T_(median) is higher than 98.0° C., ComonomerDistribution Index is defined as 0.95;

(G) Obtain Maximum peak height from CEF comonomer distribution profileby searching each data point for the highest peak from 35.0° C. to119.0° C. (if the two peaks are identical, then the lower temperaturepeak is selected); half width is defined as the temperature differencebetween the front temperature and the rear temperature at the half ofthe maximum peak height, the front temperature at the half of themaximum peak is searched forward from 35.0° C., while the reartemperature at the half of the maximum peak is searched backward from119.0° C., in the case of a well defined bimodal distribution where thedifference in the peak temperatures is equal to or greater than the 1.1times of the sum of half width of each peak, the half width of theinventive ethylene-based polymer composition is calculated as thearithmetic average of the half width of each peak; (H) Calculate thestandard deviation of temperature (Stdev) according the followingEquation:

${Stdev} = \sqrt{\sum\limits_{35.0}^{119.0}\; {\left( {T - T_{p}} \right)^{2}*{w_{T}(T)}}}$

Creep Zero Shear Viscosity Measurement Method

Zero-shear viscosities are obtained via creep tests that were conductedon an AR-G2 stress controlled rheometer (TA Instruments; New Castle,Del.) using 25-mm-diameter parallel plates at 190° C. The rheometer ovenis set to test temperature for at least 30 minutes prior to zeroingfixtures. At the testing temperature a compression molded sample disk isinserted between the plates and allowed to come to equilibrium for 5minutes. The upper plate is then lowered down to 50 μm above the desiredtesting gap (1.5 mm). Any superfluous material is trimmed off and theupper plate is lowered to the desired gap. Measurements are done undernitrogen purging at a flow rate of 5 L/min. Default creep time is setfor 2 hours.

A constant low shear stress of 20 Pa is applied for all of the samplesto ensure that the steady state shear rate is low enough to be in theNewtonian region. The resulting steady state shear rates are in therange of 10⁻³ to 10⁻⁴ s⁻¹ for the samples in this study. Steady state isdetermined by taking a linear regression for all the data in the last10% time window of the plot of log (J(t)) vs. log(t), where J(t) iscreep compliance and t is creep time. If the slope of the linearregression is greater than 0.97, steady state is considered to bereached, then the creep test is stopped. In all cases in this study theslope meets the criterion within 2 hours. The steady state shear rate isdetermined from the slope of the linear regression of all of the datapoints in the last 10% time window of the plot of c vs. t, where ε isstrain. The zero-shear viscosity is determined from the ratio of theapplied stress to the steady state shear rate.

In order to determine if the sample is degraded during the creep test, asmall amplitude oscillatory shear test is conducted before and after thecreep test on the same specimen from 0.1 to 100 rad/s. The complexviscosity values of the two tests are compared. If the difference of theviscosity values at 0.1 rad/s is greater than 5%, the sample isconsidered to have degraded during the creep test, and the result isdiscarded.

Zero-Shear Viscosity Ratio (ZSVR) is defined as the ratio of thezero-shear viscosity (ZSV) of the branched polyethylene material to theZSV of the linear polyethylene material at the equivalent weight averagemolecular weight (Mw-gpc) according to the following Equation:

${ZSVR} = {\frac{\eta_{0B}}{\eta_{0L}} = \frac{\eta_{0B}}{2.29 \times 10^{- 15}M_{w - {gpc}}^{3.65}}}$

The ZSV value is obtained from creep test at 190° C. via the methoddescribed above. The Mw-gpc value is determined by the conventional GPCmethod. The correlation between ZSV of linear polyethylene and itsMw-gpc was established based on a series of linear polyethylenereference materials. A description for the ZSV-Mw relationship can befound in the ANTEC proceeding: Karjala, Teresa P.; Sammler, Robert L.;Mangnus, Marc A.; Hazlitt, Lonnie G.; Johnson, Mark S.; Hagen, CharlesM., Jr.; Huang, Joe W. L.; Reichek, Kenneth N. Detection of low levelsof long-chain branching in polyolefins. Annual TechnicalConference—Society of Plastics Engineers (2008), 66th 887-891.

¹H NMR Method

3.26 g of stock solution is added to 0.133 g of polyolefin sample in 10mm NMR tube. The stock solution is a mixture of tetrachloroethane-d₂(TCE) and perchloroethylene (50:50, w:w) with 0.001M Cr³⁺. The solutionin the tube is purged with N₂ for 5 minutes to reduce the amount ofoxygen. The capped sample tube is left at room temperature overnight toswell the polymer sample. The sample is dissolved at 110° C. withshaking The samples are free of the additives that may contribute tounsaturation, e.g. slip agents such as erucamide.

The ¹H NMR are run with a 10 mm cryoprobe at 120° C. on Bruker AVANCE400 MHz spectrometer.

Two experiments are run to get the unsaturation: the control and thedouble pre-saturation experiments.

For the control experiment, the data is processed with exponentialwindow function with LB=1 Hz, baseline was corrected from 7 to −2 ppm.The signal from residual ¹H of TCE is set to 100, the integral I_(total)from −0.5 to 3 ppm is used as the signal from whole polymer in thecontrol experiment. The number of CH₂ group, NCH₂, in the polymer iscalculated as following:

NCH₂=I_(total)/2

For the double presaturation experiment, the data is processed withexponential window function with LB=1 Hz, baseline was corrected from6.6 to 4.5 ppm. The signal from residual ₁H of TCE is set to 100, thecorresponding integrals for unsaturations (I_(vinylene),I_(trisubstituted), I_(vinyl) and I_(vinylidene)) were integrated basedon the region shown in the graph below

The number of unsaturation unit for vinylene, trisubstituted, vinyl andvinylidene are calculated:

N_(vinylene)=I_(vinylene)/2

N_(trisubstituted)=I_(trisubstitute)

N_(vinyl)=I_(vinyl)/2

N_(vinylidene)=I_(vinylidene)/2

The unsaturation unit/1,000,000 carbons is calculated as following:

N_(vinylene)/1,000,000C=(N_(vinylene)/NCH₂)*1,000,000

N_(trisubstituted)/1,000,000C=(N_(trisubstituted)/NCH₂)*1,000,000

N_(vinyl)/1,000,000C=(N_(vinyl)/NCH₂)*1,000,000

N_(vinylidene)/1,000,000C=(N_(vinylidene)/NCH₂)*1,000,000

The requirement for unsaturation NMR analysis includes: level ofquantitation is 0.47±0.02/1,000,000 carbons for Vd2 with 200 scans (lessthan 1 hour data acquisition including time to run the controlexperiment) with 3.9 wt % of sample (for Vd2 structure, seeMacromolecules, vol. 38, 6988, 2005), 10 mm high temperature cryoprobe.The level of quantitation is defined as signal to noise ratio of 10.

The chemical shift reference is set at 6.0 ppm for the ¹H signal fromresidual proton from TCT-d2. The control is run with ZG pulse, TD 32768,NS 4, DS 12, SWH 10,000 Hz, AQ 1.64 s, D1 14 s. The double presaturationexperiment is run with a modified pulse sequence, O1P 1.354 ppm, O2P0.960 ppm, PL9 57 db, PL21 70 db, TD 32768, NS 200, DS 4, SWH 10,000 Hz,AQ 1.64 s, D1 1 s, D13 13 s. The modified pulse sequences forunsaturation with Bruker AVANCE 400 MHz spectrometer are shown below:

  ;lc1prf2_zz prosol relations=<lcnmr> #include <Avance.incl> “d12=20u”“d11=4u” 1 ze d12 pl21:f2 2 30m d13 d12 pl9:f1 d1 cw:f1 ph29 cw:f2 ph29d11 do:f1 do:f2 d12 pl1:f1 p1 ph1 go=2 ph31 30m mc #0 to 2 F0(zd) exitph1=0 2 2 0 1 3 3 1 ph29=0 ph31=0 2 2 0 1 3 3 1

Turf Yarn Test Methods

The following test methods were used to measure various properties ofthe turf yarns, prepared as described above on a three oven process.

Linear Weight: The linear weight (in dtex) of a monofilament is equal tothe weight in grams of 50 meters of the monofilament and extrapolatingthat measurements to obtain the weight of 10 km of the monofilament.

Stability and Residual Elongation: Stability and residual elongationwere measured on a Zwick tensile tester on a filament length of 260 mmand an extension rate of 250 mm/min until the filament breaks. Stabilityis defined as the tensile force at break divided by the linear weight(dtex). Residual elongation is the strain at break.

Shrink: The shrink of a monofilament (expressed as the percentagereduction in length of a 1 meter sample of the monofilament) is measuredby immersing the monofilament for 20 seconds in a bath of silicon oilmaintained at 90° C.

Curl: Curl is measured by taking yarn from the bobbin and bending 2×8filaments into a brush and fixing them by tape. The brush is hung on ahook for 5 minutes at 90° C. in a hot air oven. Thereafter, a photographis taken of the brush and the spread of the fibers (10 in FIG. 1) attheir tip is divided by the length of the brush (20 in FIG. 1) tocalculate the curl.

Unless otherwise stated, implicit from the context or conventional inthe art, all parts and percentages are based on weight. Allapplications, publications, patents, test procedures, and otherdocuments cited, including priority documents, are fully incorporated byreference to the extent such disclosure is not inconsistent with thedisclosed compositions and methods and for all jurisdictions in whichsuch incorporation is permitted.

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.

1. An artificial turf comprising: a turf yarn prepared from anethylene-based polymer composition comprising: less than or equal to 100percent by weight of the units derived from ethylene; and less than 30percent by weight of units derived from one or more α-olefin comonomers;wherein said ethylene-based polymer composition is characterized byhaving a Comonomer Distribution Constant of equal to or greater than 40,a vinyl unsaturation of less than 100 vinyls per one million carbonatoms present in the backbone of the ethylene-based polymer composition;a zero shear viscosity ratio (ZSVR) equal to or greater than 1.75; adensity in the range of 0.915 to 0.930 g/cm³, a melt index (1₂) in therange of from 0.8 to 5 g/10 minutes, a molecular weight distribution(M_(w)/M_(n)) in the range of from 2 to 3.6, and a molecular weightdistribution (M_(z)/M_(w)) equal to or less than 3; and wherein the turfyarn exhibits one or more of the following properties (a) shrink of lessthan 4.8%, and (b) curl of less than 0.5.
 2. The artificial turfaccording to claim 1, wherein the turf yarn exhibits a shrink of lessthan 4.5%.
 3. The artificial turf according to claim 1, wherein the turfyarn exhibits a curl of less than 0.4.
 4. The artificial turf accordingto claim 1, wherein the ethylene-based polymer composition has an I₂from 2 to
 4. 5. The artificial turf according to claim 1, wherein theturf yarn exhibits an elongation at break of at least 65%.
 6. Theartificial turf according to claim 1, wherein the turf yarn exhibits astability of 0.9 cN/dtex.
 7. A method of preparing an artificial turfcomprising: selecting an ethylene-based polymer composition comprising:less than or equal to 100 percent by weight of the units derived fromethylene; and less than 30 percent by weight of units derived from oneor more α-olefin comonomers; wherein said ethylene-based polymercomposition is characterized by having a Comonomer Distribution Constantof equal to or greater than 40, a vinyl unsaturation of less than 100vinyls per one million carbon atoms present in the backbone of theethylene-based polymer composition; a zero shear viscosity ratio (ZSVR)equal to or greater than 1.75; a density in the range of 0.915 to 0.930g/cm³, a melt index (I₂) in the range of from 0.8 to 5 g/10 minutes, amolecular weight distribution (M_(w)/M_(n)) in the range of from 2 to3.6, and a molecular weight distribution (M_(z)/M_(w)) equal to or lessthan 3; and preparing a turf yarn from the ethylene-based polymercomposition.
 8. The method according to claim 7, wherein the turf yarnexhibits one or more of the following properties (a) shrink of less than4.8%, and (b) curl of less than 0.5.
 9. The method according to claim 7,wherein the turf yarn exhibits a shrink of less than 4.5%.
 10. Themethod according to claim 7, wherein the turf yarn exhibits a curl ofless than 0.4.
 11. The method according to claim 7, wherein theethylene-based polymer composition has an I₂ from 2 to
 4. 12. The methodaccording to claim 7, wherein the turf yarn exhibits an elongation atbreak of at least 65%.
 13. The method according to claim 7, wherein theturf yarn exhibits a stability of 0.9 cN/dtex.